Slope-break belt is the basis of sequence stratigraphic classification and correlation, stratigraphic architectural analysis and sequence model establishment. A lot of researches have been done on different types of slope breaks, however, most of them focused on the analysis of a single slope-break belt. The stratigraphic sequence analysis of the Pearl River Mouth basin in the northern South China Sea shows that there are double slope breaks since the Neogene in the basin, that is, the sedimentary slope-break belt of the continental shelf and the geomorphic slope-break belt of the shelf edge exist simultaneously, and the controls of different slope-break belts on sedimentary sequence are various. Based on the comparison between the two types of slope-break belts from the aspects of formation background, development and evolution, topography and geomorphology characteristics, and sedimentary systems, it is believed that the formation of the geomorphic slope-break belt is closely related to the tectonic action, as a result, three types of stratigraphic sequences are formed including four partitioned, three partitioned and two partitioned system tracts, respectively. The formation of sedimentary slopes is obviously controlled by paleogeomorphology, sediment supply process and non-equilibrium unloading, and the last two types of stratigraphic sequences are dominant